Participants will have a blood test and a physical examination before receiving voriconazole. They will receive voriconazole twice a day either as an infusion into a vein or as tablets taken by mouth. Adult patients will be asked to provide a blood sample any time after the first dose of voriconazole to be used for developing a test to measure voriconazole concentration in the blood. Patients will be evaluated about 10 days after starting treatment and then at least once every 4 weeks with a symptom check and blood test.